Traffic signals are crucial to helping drivers properly and safely navigate the roadway system. But when they are obstructed, everyone on the roadway is at risk.
The City of Walnut Creek in California would often conduct regular inspections to ensure its traffic signals were clearly visible to drivers, but this process could be labor intensive and involved trained personnel to verify visibility for traffic signal lights. City officials wanted to improve the process to be safer for the workers and be more proactive.
Their solution was the Safe Sightings of Signs and Signals (SSOSS) Software. The innovation added an automated process to assessing traffic signal visibility using readily available, off-the-shelf hardware components such as a cell phone with built-in camera and lots of storage, a GPS receiver, a cell phone mount for the windshield, and a laptop computer.
After setting up a smartphone on the vehicle dash to record GPS points and video, the vehicle is driven through as many intersection approaches as desired, ensuring data is being recorded the entire time. Once the route is completed, the collected data/video is transferred to a computer and processed using the SSOSS program to save images of each of the driven intersection approaches.
Matt Redmond, associate transportation engineer with the City of Walnut Creek, says, “I was very surprised at the accuracy of the data. It [the SSOSS] just gives you clear insight about whether a signal is blocked or not. With this software-based system, all of our agency’s intersections, about 350 approaches, can be checked for sight distance in a single day without anyone getting out of their car. Moreover, this solution has promoted a proactive approach to ensure traffic signals are visible to drivers, rather than a reactive approach that may leave traffic signals obstructed for longer than necessary.”
The innovative solution has resulted in significant time savings and increased productivity for the city’s staff. According to Redmond, conducting sight distance checks could take 15 to 45 minutes per intersection, depending on location, which includes parking and measuring the required sight distance for each of the four approaches.
“Implementing the software-based system required a lot of driving and recording data, but once you have the information, you don’t have to do it again,” Redmond says. “There were so many times, I didn’t think I could do it. It required me to learn to program and then I had to keep wracking my brain about how to get this angle or that angle.”
Redmond’s advice to anyone on using innovative solutions is threefold: 1) Innovation takes time, and this was not an overnight solution; 2) Explore the potential for an innovation by asking “What if we could do this” or “What if this is a possibility?”; and 3) Collaboration is important—“I spent a lot of time talking to other professionals about this innovation, making sure the solution makes sense to them,” Redmond says.
The project won the Pioneer Award in the 2023 Build a Better Mousetrap national program.
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